WPP is braced for another bruising encounter with shareholders over pay, after the Association of British Insurers slapped the marketing group with an ‘amber top’ warning.

The influential investor group, which represents more than 300 groups holding about 17 per cent of the FTSE100, issued its second-highest level of disapproval, flagging pay as ‘an issue to consider prior to voting’.

WPP, which owns the JWT and Finsbury agencies, has thumbed its nose at investors by controversially hiking the pay of chief executive Sir Martin Sorrell by a record 70 per cent.

Pay: WPP, which owns the JWT and Finsbury agencies, has thumbed its nose at investors by controversially hiking the pay of chief executive Sir Martin Sorrell by a record 70 per cent

Shareholders will have the chance to vote on the proposal at an annual meeting held at London’s Shard on June 25.

The ABI suggested members examine the remuneration report ‘to be satisfied with the level of disclosure provided by the company with regard to the targets required and achieved under the annual bonus’.

The increase comes despite constant investor protests over excessive boardroom pay, with 60 per cent voting down the group’s remuneration report in 2012.

But WPP, which has held extensive talks with shareholders, decided to push ahead, giving Sorrell his biggest reward package in 10 years.

He will take home £29.8million in total annual remuneration, up from £17.5million the previous year. But this is below the £50million he received in 2005.

WPP’s annual report shows Sorrell’s basic pay dropped to £1.1million from £1.3million. But his long-term incentive plan doubled to £22.6million from £11.3million while a different scheme produced £4million.

The ABI draws attention to Sorrell’s potential ‘award opportunity under the executive performance share plan of 975 per cent of salary’ but points out that this new scheme was approved at last year’s annual general meeting.

Sorrell has brushed off investors’ concerns in the past saying: ‘The fundamental point is I do see it as an entrepreneurial exercise.’